So I got excited and bought some blank PBT spherical keycaps from Signature Plastics for my Kinesis Advantage. I can tell you after only typing on them for a few minutes, it's a huge improvement in space and feel.

I have hypothesized that the Maltron feels spacier than the Kinesis Advantage because the Maltron has spherical keycaps compared to the Advantage's DCS family keycaps. I did some rough measurements, and the spherical keycaps have less surface area on top of the keycap, so it does increase the space between each keycap. I also enjoy the uniform feel because all the keycaps are the exact same shape. On the Kinesis Advantage, I didn't like how the rows were all different heights, and with the spherical keycaps, the rows are almost flush.

Without further ado, here are some pictures. I couldn't resist a ridiculous American flag design theme to the keycaps:

They ran a $1 per key cap for PBT, plus $4.50 in shipping. So for 58 keycaps, it was $62.50. Shipping to other countries will be higher, of course. All of it is a bit steep, I know, but it seems nobody sells large sets of spherical keycaps.

I didn't do the thumb clusters because i like how Kinesis arranged them with the different heights and angles. I might do it eventually, because the thumb clusters are starting to shine after a few months of moderate use. And the feel of the PBT keycaps is a whole lot better.

Hi, thanks for the DSA information, i have bought some DCS keycaps from wasdkeyboards in order to 'type-friendly' the key64.org keyboard, but right now when i am typing on it I found it really weird to have a dcs keycaps on an ergonomic layout, that seems to make sense on a row based keyboard but on a ergonomic keyboard it have been painful to type with DCS keycaps, so i was looking at the DSA keycaps as a replacement and then i found this thread, well it seems the way to go, at least i will have more options for colors and size and I won't be limited to row type on a certain sizes, for example: the 1.25x keycaps which only exists on a row1 while i need on rows 2,3,4 and 5, or the 1.75x or 1.50 which doesn't fit nicely with each others, so that's my experience, i will tell you how things will evolve using DSA keycaps as soon as i receive them.

Apologies for the extreme thread necro, but as I hit this through Google while searching for the same info I figured you might appreciate a current answer as well with Kinesis owners searching for blanks. Kinesis is actually selling them through their site now. I'm looking to get a set, I'm just hoping they haven't changed the key layout too much from the PS2 Classic to the newer USB Advantage which is what they are selling them for.